Reusable blade hub assembly

ABSTRACT

A surgical instrument including a reusable and sterilizable hub assembly and a releasably connectable disposable blade assembly allows multiple reuse of the hub assembly in conjunction with single use disposable blade assemblies.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/992,188 filed Jan. 11, 2016 titled “Reusable Blade Hub Assembly,”which is a continuation of U.S. application Ser. No. 13/472,895 filedMay 16, 2012 (now U.S. Pat. No. 9,232,958) and titled “Reusable BladeHub Assembly.” Both of the noted applications are incorporated byreference herein as if reproduced in full below.

FIELD OF INVENTION

The present disclosure relates generally to surgical instruments and,more specifically, to a rotary surgical instrument for cutting tissue.

BACKGROUND

Powered arthroscopic surgical instruments typically include a rigid,stationary outer tube within which a rigid inner tube is rotated by amotor. A cutting implement, such as a blade or abrading burr, isdisposed on the distal end of the inner tube. Tissue or bone is exposedto the cutting implement through an opening in the distal end of theouter tube, and tissue or bone fragments cut by the rotating blade orburr are drawn through the interior of the inner tube, along withirrigating fluid, by the use of suction applied at the proximal end ofthe instrument.

A motorized attachment engages a hub, typically on the inner tube, androtates the inner tube within the outer tube for providing cuttingmovement and force. The motorized attachment also incorporates a suctionattachment for evacuating cut matter from a surgical extraction sitethrough the hollow tubes. Several surgical instruments of variouscomplementary functions are often employed when performing surgicalprocedures, one function of which is the controlled cutting andevacuation of tissue and bone fragments.

Conventional single use arthroscopic blades typically use a non-reusableplastic hub assembly permanently integrated with metallic outer tubesand inner tubes containing cutting edges. The hub assembly is disposedof in its entirety at the conclusion of an operating procedure. Theconventional hub assembly components including an outer hub and innerhub are typically each formed from a single piece of injection moldedplastic.

Conventional multiple use arthroscopic blades include a metallic hubassembly permanently integrated with metallic tubes containing cuttingedges. This assembly is reprocessed at the conclusion of each use andthe cutting edges are periodically reconditioned.

SUMMARY

Conventional approaches to reuse of arthroscopic surgical instrumentssuffer from shortcomings in cost and reusability because conventionalsurgical instruments employ blades and tubes that are permanentlyaffixed to a corresponding inner hub and outer hub, respectively.Therefore, the entire blade, tube, hub assembly must be disposed orsomehow effectively sterilized. Configurations disclosed herein arebased, in part, on the observation that a disposable blade assembly canbe designed to be releasably engaged to a reusable hub assembly. The hubassembly is also designed to be sturdier and more easily sterilized. Itwould be beneficial, therefore, to provide a reusable and sterilizablehub assembly, and a disposable blade assembly, releasably connectable tothe hub assembly to avoid the need to dispose of hub components. Such anassembly would also avoid any problems associated with trying tosterilize tubes and blades while they are affixed to hubs and driveshafts.

Accordingly, configurations herein substantially overcome theshortcomings of conventional surgical instruments by combining areusable hub assembly having an outer hub and an inner hub insertableinto the outer hub with a disposable blade assembly releasablyconnectable to the hub assembly. The disposable blade assembly has anouter tube releasably connectable to the outer hub, and an inner tubereleasably connectable to the inner hub. Such an instrument reduces thedisposable assembly to a disposable blade assembly including metalliccutting members (e.g., outer tube edgeform and inner tube edgeform). Thedisposable blade assembly which no longer includes the inner and outerhub provides a lower unit cost and eliminates problems associated withattempts to sterilize the blade assemblies especially when the bladesare permanently fixed to hubs or drive shafts. Other savings includereduced packaging cost, reduction in sterilization costs, lower disposalcosts, reduced environmental impact due to elimination of disposableplastic components, and diminished environmental impact due to reductionin packaging volume. In one embodiment, the reusable blade hub assemblycan be attached to existing motor drive units (MDUs) and existingcontrols, thus avoiding the need to acquire a new MDU, controls or anysurgical technique modification.

In further detail, the disclosed reusable and sterilizable hub assemblyincludes an outer hub having an inner hub cavity, an outer tubereceiving channel for releasably receiving a disposable outer tube andan outer tube retainer. The hub assembly further includes an inner hubinsertable into the inner hub cavity of the outer hub comprising aninner channel for receiving a disposable inner tube, the inner channelhaving an opening for releasably engaging the disposable inner tube.

By reusing the hub assembly, optional coding magnets which interact withHall-effect devices to identify the type of surgical instrument can bereused, because in the disclosed configurations the magnets are embeddedin the reusable hub assembly. Such an assembly allows attachment andremoval of disposable metallic cutting members. The attachment andlocating mechanisms are integrated into the hub assembly along withcorresponding features incorporated into the inner and outer tubes.

In order to operate correctly, the disposable outer tube is fixed bothrotatably and axially with respect to the reusable outer hub. Likewisethe disposable inner tube is fixed both rotatably and axially at aproximal end with respect to the reusable inner hub. In order to bedisposable, the outer tube is easily releasable from the outer hub andthe inner tube is easily releasable from the inner hub. In other words,after the disposable blade assembly is inserted into the hub assembly,the outer tube will not substantially rotate with respect to the outerhub or slip into or out of the outer hub, and the inner tube rotates inconjunction with the inner hub without slipping. Many of the featureswhich allow releasability and provide rotational and axial retention arepredominantly associated with the reusable hub assembly to minimizecosts associated with the disposable components. Some of these featuresare described below.

A disposable blade assembly for use with a reusable hub assemblycomprising an inner hub and an outer hub, the disposable blade assemblyincludes an elongate outer tube having a distal region with an opening,and an outer cross section for releasable engagement with an outer hub.The blade assembly further includes an elongate inner tube rotatablydisposed at least partially within the elongate outer tube, having aproximal end cross section with a profile for releasable engagement witha corresponding inner hub inner channel, and a distal region comprisinga cutting member. The cutting member is adjacent to the outer tubeopening and permits resection of bodily tissue. The disposable bladeassembly allows for rapid assembly of the blade components (i.e., innerand outer tubes) together with the hub assembly in an operating roomenvironment, without utilization of tools or additional hardware. Uponcompletion of the surgical procedure, the surgical instrument can bedisassembled to allow the hub assembly to undergo a reprocessing cycle,while the single use cutting blades are disposed.

In an example arrangement, the outer hub geometry provides fullcompatibility with existing handpieces (MDUs) by including an MDUlatching member incorporated into the hub assembly. In this arrangement,the hub assembly has a metal construction and is autoclavable. The outertube has an asymmetrical outer cross section matching the outer hubreceiving channel cross section, to orientate an edgeform opening inrelation to the MDU, and to prevent radial dislocation of the tube. Thehub assembly includes a retainer. The retainer includes a separateretaining cap joined via threaded attachment to a fixed retaining memberdisposed at a distal region of the outer hub. In other arrangements,inner tubes have differing non-circular cross sections. In a particulararrangement, the inner tube has an oval cross section extending for aportion of the proximal end of the inner tube while the remainingportion of the tube has a circular cross section. The oval cross sectioncorresponds to an inner hub inner channel cross section for effectivetorque transfer between the inner hub and the inner tube.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthe specification, illustrate the embodiments of the present disclosureand together with the written description serve to explain theprinciples, characteristics, and features of the disclosure. Theforegoing and other objects, features and advantages of the inventionwill be apparent from the following description of particularembodiments of the invention, as illustrated in the accompanyingdrawings in which like reference characters refer to the same partsthroughout the different views. The drawings are not necessarily toscale, emphasis instead being placed upon illustrating the principles ofthe invention. In the drawings:

FIG. 1A is a perspective view of an assembled surgical instrument asdisclosed herein;

FIG. 1B is a cross sectional side view of the surgical instrument ofFIG. 1A;

FIG. 1C is an exploded view of the surgical instrument of FIG. 1A;

FIG. 2 shows a cross section view of a hub assembly of the surgicalinstrument of FIG. 1A, including an outer tube retainer;

FIG. 3 shows a cross section view of a disposable blade assembly for usewith the hub assembly of FIG. 2 ;

FIG. 4 is a perspective view of the outer hub of FIG. 2 including afixed member of the outer tube retainer;

FIG. 5 is a perspective view of a separate outer tube retaining memberwhich engages the fixed member of the outer tube retainer of FIG. 4 ;

FIG. 6A is a perspective view of a collet chuck embodiment of theseparate outer tube retaining member;

FIG. 6B is a perspective view of a flexible collet of the collet chuckembodiment of FIG. 6A;

FIG. 6C is a perspective view of an alternate collet used with colletchuck embodiment of FIG. 6A;

FIG. 6D is a section view of a nose cap of the collet chuck embodimentof FIG. 6A;

FIG. 7A shows a view of another embodiment of the distal end of theouter hub assembly of FIG. 2 ;

FIG. 7B shows a cross section view of the outer cross section of anouter tube for releasable engagement with the outer hub outer tube ofFIG. 7A;

FIG. 7C shows a view along a length of the outer tube of FIG. 7C.

FIG. 8A shows a perspective view of another embodiment of the distal endof an inner hub of the hub assembly of FIG. 2 ;

FIG. 8B shows a cross section view of FIG. 8A taken along lines 8B-8B ofFIG. 8A;

FIG. 8C shows a cross section view of the outer non-circular crosssection of the inner tube for releasable engagement with the inner hubouter tube of FIG. 8A;

FIG. 9A shows a perspective view of another embodiment of an inner hubof the hub assembly of FIG. 2 ;

FIG. 9B shows a perspective view of a flanged proximal end of an innertube for releasable engagement with the inner hub of FIG. 9A;

FIG. 9C shows a perspective view of the proximal and distal regions ofthe inner tube of FIG. 9B;

FIGS. 10A and 10B show a cross section view of another embodiment of aswagable outer tube for releasable engagement with the outer hub of thesurgical instrument of FIG. 1A;

FIG. 11 is a perspective view of a pin and groove embodiment of theseparate outer tube retaining member which engages the fixed member ofthe outer tube retainer similar to the retainer of FIG. 4 ;

FIG. 12 is a cross section view of another embodiment of the surgicalinstrument of FIG. 1A having dual locking mechanisms used to secure thedisposable blade assembly within the hub assembly; and

FIG. 13 is a perspective view of a proximal end of a disposable outertube having alignment tabs which engage an outer hub as disclosedherein.

DETAILED DESCRIPTION

A surgical instrument including a reusable and sterilizable hub assemblyand a releasably connectable disposable blade assembly allows multiplereuse of the hub assembly in conjunction with a single use disposableblade assembly. Depicted below are example configurations of thesurgical instrument as disclosed and claimed herein. The disposableblade assembly includes a disposable outer tube and disposable innertube. The disposable outer tube is fixed both rotatably and axially withrespect to the reusable outer hub. Likewise a disposable inner tube isfixed both rotatably and axially at a proximal end with respect to thereusable inner hub. In order to be disposable, the outer tube is easilyreleasable from the outer hub and the inner tube is easily releasablefrom the inner hub.

FIG. 1A is a view of a surgical instrument 100 as disclosed herein,including a reusable and sterilizable hub assembly 110 and a disposableblade assembly 150 releasably connectable to the hub assembly 110. Thehub assembly 110 includes an outer hub 112 and an inner hub 130 which isinsertable into the outer hub 112. In operation, a motor drive unit(MDU) 10 connects to an extension 132 on the inner hub 130. Details of asimilar MDU 10 are described in U.S. Pat. No. 5,133,729, which isentitled “Motor-Driven Hand-Piece for a Surgical Tool,” U.S. Pat. No.6,090,122, which is entitled “Surgical Instrument Handpiece and System,”and both are incorporated by reference.

FIG. 1B is a cross sectional side view of FIG. 1A showing additionaldetails of surgical instrument 100. The disposable blade assembly 150includes an outer tube 160 and an inner tube 170 rotatably disposed atleast partially within the outer tube 160. In one embodiment, thedisposable blade assembly 150, or separately the inner tube 170 or theouter tube 160, can be quickly released from the hub assembly 110without requiring any special tools. This is useful, for example, tochange blades during an operation.

Now referring to FIGS. 1C and 2 , there are several ways to assemble thesurgical instrument 100 two of which described below:

A first method shown in FIG. 1C for assembling the surgical instrument100 having a reusable hub assembly 110 and a disposable blade assembly150 includes:

aligning a proximal end cross section of an inner tube 170 with an innerhub inner channel opening 136;

inserting the inner tube proximal end into the inner channel until fullyseated against a bottom of an inner hub stop 138 (FIG. 2 );

aligning a proximal end cross section of an outer tube 160 with an outerhub receiving channel opening 124 (FIG. 2 );

inserting the proximal end of the outer tube 160 into the outer hubreceiving channel 124 until seated against a bottom of the outer hubreceiving channel;

engaging an outer tube retainer 114 to retain the outer tube whichincludes an O-ring 128;

assembling the inner hub 130 into the outer hub 112; and

finally latching the surgical instrument 100 onto the motor drive unit10.

A second method includes:

inserting the proximal end of the blade assembly 150 into the distal endof the hub assembly 110;

manipulating the inner tube proximal end until fully seated against theinner hub stop 138 of the inner channel;

manipulating the outer tube 160 proximal end until seated against thebottom of the outer hub receiving channel 124; and

engaging an outer tube retainer 114 to retain the outer tube 160; and

finally latching the surgical instrument 100 onto the motor drive unit10.

Now referring to FIGS. 2 and 3 , the hub assembly 110 includes an outerhub 112 having an inner hub cavity 122, and an outer tube receivingchannel 124 for releasably receiving the disposable outer tube 160 ofthe disposable blade assembly 150. The outer hub 112 includes an outertube retainer 114 including alignment and retaining features. The hubassembly 110 further includes an inner hub 130 insertable into the innerhub cavity 122 of the outer hub 112. The inner hub includes an innerchannel 134 for receiving the disposable inner tube 170 of thedisposable blade assembly 150, the inner channel having an opening 136for releasably engaging the disposable inner tube 170.

In one embodiment, the purpose of the retainer 114 is to releasably,rotatably fix and axially retain the disposable outer tube 160. Inanother embodiment where the outer tube 160 is partially closed on thedistal end, the inner tube 170 is also axially retained. After assembly,the disposable outer tube is prevented from advancing distally by theouter tube retainer 114. During operation the disposable outer tube isprevented from rotating with respect to the outer hub by the outer tuberetainer 114 and additional features described below. It will beappreciated that there are many ways to retain the outer tube, includingbut not limited to a snap fit system, a compressible tapered seal,splined tabs, and a collet chuck. Also shown is a stop member 138disposed within the inner channel 134 to prevent proximal advancement ofthe inner tube 170.

In one embodiment, the outer hub 112 is a one piece machined metalcomponent. In this embodiment the inner hub 130 is also one piecemachined metal component. While in this embodiment the outer hub 112 andinner hub 130 are made from stainless steel to render the instrumentreadily sterilizable and reusable, alternatively, the outer hub and theinner hub can be made from other materials including but not limited tonon-ferrous metals, polymers, reinforced polymers such as glass filledand carbon fiber.

Referring again to FIG. 3 the disposable blade assembly 150 includes adisposable elongate outer tube 160 having a proximal end 166, a distalregion 162 and an opening 164 disposed in the distal region 162 of theouter tube 160. The outer tube 160 has an outer cross section 168 (asshown in cross section in FIG. 7B for one embodiment) for releasableengagement with an outer hub 112. The disposable blade assembly 150further includes a disposable elongate inner tube 170 rotatably disposedat least partially within the elongate outer tube 160. The inner tube170 has a proximal end cross section 178 (as shown in cross section inFIG. 8C for one embodiment) having a cross-section for releasableengagement with a corresponding inner hub inner channel 134 (FIG. 2 ), adistal region 180 at a distal end 182 and a cutting member 184 disposedin the distal region 180 of the inner tube 170. The cutting member 184is adjacent the outer tube opening 164 to permit resection of bodilytissue. In various embodiments the cutting member can be a blade or aburr. In an embodiment which is compatible with conventional handpieces,the inner hub 130 includes an opening 140 (FIG. 1A) that permitsmaterial drawn through inner tube to pass into an aspiration channel(not shown) of the handpiece (not shown).

Referring to FIGS. 4 and 5 , the outer tube retainer 114 includes afixed member 118 disposed at a distal region of the outer hub 112, and aseparate retaining member 116. In one embodiment the outer tube retainerfixed member 118 includes a threaded region 410 and the outer tubeseparate retaining member 116 is a removable cap 500 having a threadedregion 510 to connect to threaded region 410.

The outer tube 160 and the outer hub 112 are secured in rotational andaxial communication by any suitable manner, such as threaded regions 410and 510, respectively, which, after being engaged, serve to prevent theouter tube 160 from sliding back out of the outer hub 112. A snap fitsystem adapted to mate with a corresponding snap-fit connection on aproximal end of the outer hub, a pin and groove system adapted to matewith a corresponding pin and groove system (FIG. 11 ) connection on aremovable cap or frictional resilient arrangement may be used instead ofthe thread regions to accomplish the same goal. In one embodiment, theO-ring 128 (FIG. 1C) is installed on the outer tube 160 and iscompressed between the cap 500 and the outer hub 112 to provide a sealfor the aspiration channel.

As shown in FIGS. 6A-6D an alternative retaining mechanism includes acollet chuck 600. The collet chuck 600 includes a collet 610 and a nosecap 620. The collet chuck 600 engages an outer tube retainer fixedmember 630 similar to outer tube retainer fixed member 118. The colletchuck 600 allows releasing of the disposable blade assembly 150 withoutcompletely removing the nose cap 620. In one embodiment, the collet 610(FIG. 6B) is a combination of a flexible portion 640 and a ridgedportion 650. Such a retainer can advantageously provide a secure fit forimproved retention of the out hub. The flexible portion 640 accommodatesvarious inner tube diameters, thus eliminating the need for a collet foreach diameter. The flexible portion 640 also provides sealing for thesuction attachment. In other embodiments, the material used in thecollet could be any type metal or a polymer embedded into any type offlexible material. The nose cap 620 (FIG. 6D) includes a threadedportion 660 to engage with the outer tube retainer fixed member 118.FIG. 6C shows an alternate collet having open slots 672 a-672 n and 674a-674 n.

Now referring to FIGS. 7A-7C, a hub assembly 710 includes an outer hub712 with an outer tube receiving channel cross section 720 whichcorresponds to an outer cross section 740 of the disposable outer tube760. In one embodiment, the outer tube receiving channel cross section720 has an asymmetrical cross section (not shown), and in anotherembodiment the outer tube receiving channel cross section 720 has akeyed symmetrical cross section with key feature 732, to orient anedgeform opening 762 in the disposable outer tube 760 with respect to ahandpiece attached to the hub assembly 710.

FIG. 7B shows the outer cross section 740 of a disposable blade assemblydisposable elongate outer tube 760. Here, the outer cross section 740 isa keyed symmetrical cross section with key feature 742 to fit with outertube receiving channel cross section 720 and to orient the edgeformopening 762 in the disposable outer tube 760 with respect to a handpiece(MDU) attached to the outer hub. As described above, it is also possibleto use an asymmetrical outer cross section for the outer tube receivingchannel cross section 720.

Orienting the edgeform opening allows a user to grasp the surgicalinstrument attached to an MDU in a preferred position and have theopening, for example, point straight down or straight up. This featurereproduces the orientation feature of permanently fixed, non-releasableblade and hub conventional devices while maintaining releasability ofthe disposable blade assembly.

As shown in FIG. 7C, the outer cross section 740 does not need to extendthe entire length of the disposable outer tube 760 and can be formed atthe proximal end of the outer tube 760 by several methods including, butnot limited to, swaging, forming with die set or welding. In oneembodiment, length of the profile along the long axis of the disposableouter tube 760 is approximately one cm.

Now referring to FIGS. 8A-8C, an inner hub 830 includes an inner channelopening 820 which corresponds to an outer cross section 840 of adisposable inner tube 870. In one embodiment, the inner channel opening820 has a non-circular, here an oval cross section and in anotherembodiment the inner channel opening (not shown) is keyed to match a keyon the disposable inner tube (not shown).

FIG. 8C shows the outer cross section 840 of a disposable blade assemblydisposable elongate inner tube 870. Here, the outer cross section 840 isnon-circular, here an oval, to fit within inner tube channel opening820.

Now referring to FIGS. 9A-9C, an inner hub 912 has an inner hub surface920 disposed to receive a flange 940 attached to a proximal end 962 ofthe disposable inner tube 960. In one embodiment, the flange hasalignment features 942 a-942 n disposed to engage with correspondingalignment features 922 a-922 n disposed on the surface 920 of the innerhub 912. In one embodiment the alignment features 922 a-922 n arealignment tabs.

The alignment features 922 a-922 n, in conjunction with the inner hubsurface 920, provide an inner channel which, when releasably engagedwith alignment tabs 942 a-942 n, rotatably fix the disposable inner tube960 with respect to the inner hub 912. The flange connection providesadditional sealing for the aspiration channel.

Now referring to FIGS. 10A and 10B, an alternative outer tube 1010includes a swagable flange section 1012 on a proximal portion 1014 ofthe outer tube 1010. In one embodiment the outer tube 1010 is a steppedtube. During assembly the outer tube 1010 is inserted into a receivingchannel 1032 of an outer cap 1020. An outer tube separate retainingmember, here a removable cap, is threaded onto the fixed outer tuberetainer (not shown). The threading operation drives the outer tubeproximal portion 1014 into outer hub seal bosses 1040. This actioncauses the seal bosses 1040 to exert axial force on the swagable flangesection 1012, thus deforming the swagable flange section 1012 to conformthe seal bosses 1040. The result is a seal 1050 between the proximal endof the outer tube and the distal end of the outer hub.

Now referring to FIG. 11 , an alternative outer tube retainer 1114similar to retainer 114 (FIG. 2 ) is shown in an open position. Theouter tube retainer 1114 includes a fixed member 1118 disposed at adistal region of an outer hub 1112, and a separate retaining member1116. The outer tube retainer fixed member 1118 includes a “J” shapedgroove 1122 and the outer tube separate retaining member 1116 includesat least one pin 1120 to engage with the groove 1122. Here the retainersystem is a J-lock and the retaining member 1116 includes two pins 1120on opposite sides.

FIG. 12 shows dual locking tabs integrated onto inner and outer tubes. Asurgical instrument 1200 similar to surgical instrument 100 includes hubassembly 1210 and a disposable blade assembly 1250. The hub assembly1210 includes an outer hub 1212 and an inner hub 1230. The hub assembly1210 includes an outer hub 1212 having an indent 1218 disposed on ininner surface of the outer hub 1212. The disposable blade assembly 1250includes an outer tube 1260 having tabs 1262 a and 1262 b (collectivelyreferred as tabs 1262). The indent 1218 receives the tabs 1262 andretains the outer tube 1260 in conjunction with a retainer 1214. Theouter tube tabs 1262 are disposed at a proximal end portion of the outertube 1260 and in conjunction with indents 1218 prevent the outer tube1260 from being inserted too far into the outer hub 1212 and providepositive feedback of correct engagement. In one embodiment, the tabs1262 are welded onto the outer tube 1260. The hub assembly 1210 furtherincludes a retainer 1240 which is used for sealing and for retention ofthe inner hub 1230 during assembly with the disposable blade assembly1250.

The inner hub 1230 includes an inner channel 1236 having a lockingmechanism 1238 for engagement with an inner channel inner tube lockingmechanism 1272. In one embodiment, the locking mechanism 1272 includeslocking tube members 1274 a-1274 b which are tabs welded on the innertube 1270 and the locking mechanism 1238 is a slot in the inner channel1236. The locking tube members 1274 a-1274 b abut against a tab 1220disposed within an inner hub cavity of the outer hub 1212 to prevent theinner tube 1270 from moving axially with respect to the instrument 1200.In another embodiment the inner tube locking members comprise a sleevehaving dual tabs arranged on opposite sides of the sleeve, and thesleeve is welded onto the inner tube. This arrangement is useful whenthe inner tube comprises a burr and an outer tube partially enclosingthe inner tube is open at a distal end.

Now referring to FIG. 13 , an alternative disposable outer tube 1360includes a plurality of alignment tabs 1362 a-1362 n for engagement withcorresponding slots or grooves 1372 a-1372 n disposed on an innersurface of a proximal portion of an outer hub 1312. The alignment tabs1362 a-1362 n serve to rotatably fix the outer tube 1360 with respect tothe outer hub 1312 and to align an opening in the outer tube withrespect to the outer hub and in turn with respect to a handpiece.

In another embodiment, an inner hub includes internal splines to receivean inner tube having corresponding extruded splines. In yet anotherembodiment, a disposable blade assembly is secured by the compression ofa rubber or silicone seal and a retainer in conjunction with or insteadof an O-ring surrounding the outer tube.

Alternative embodiments include other component geometries and featuresto orient, retain and rotationally fix the disposable blades in the hubassembly. Other features include but are not limited to circular keyedcross sections, detent features as well as symmetrical and asymmetricaldesigns of the hub channels and the tube cross sections. In alternatearrangements, a snap fit or frictional resilient arrangement may be usedinstead of the threads and caps to retain the outer tube.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details(including hub and tube geometries) may be made therein withoutdeparting from the spirit and scope of the present application asdefined by the appended claims. Such variations are intended to becovered by the scope of this present application. As such, the foregoingdescription of embodiments of the present application is not intended tobe limiting, the full scope rather being conveyed by the appendedclaims.

What is claimed is:
 1. A reusable and sterilizable hub assemblycomprising: an outer hub extending along a longitudinal central axis anddefining an inner hub cavity, the outer hub further defining an outertube receiving channel for releasably receiving a disposable outer tubeand at least one outer tube radial protrusion extending radiallyinwardly toward the longitudinal central axis into the outer tubereceiving channel; an inner hub configured to be disposed in the innerhub cavity of the outer hub and defining an inner channel for receivingand releasably engaging a disposable inner tube and including at leastone inner tube radial protrusion extending radially inwardly toward thelongitudinal central axis into the inner channel and configured to abutand secure a plurality of tabs of the disposable inner tube; and anouter tube retainer including a separate retainer having a threadedregion, the outer tube retainer including a fixed member disposed at adistal region of the outer hub, the fixed member including a threadedregion to connect to the threaded region of the separate retainer, theseparate retainer annularly disposed about and extending along thelongitudinal central axis when connected to the outer hub, the at leastone outer tube radial protrusion of the outer hub configured to receiveand secure a plurality of tabs of the disposable outer tube inconjunction with the separate retainer.
 2. The hub assembly of claim 1,wherein the inner channel has an oval cross section at a right angle tothe longitudinal central axis.
 3. The hub assembly of claim 1, whereinthe inner hub includes a stop disposed within the inner channel.